Bone plates can be engaged to adjacent bony portions of a bone or of a bony segment to stabilize the bony portions. Anchors or fasteners, such as bone screws, can be used to engage bone plates to bony portions. To prevent the fasteners from backing out of the plate, various retaining devices have been developed for engagement or manipulation relative to the plate adjacent to or around the bone fasteners. Other retaining devices include placing a retaining cover plate over the bone plate and anchors, and thus creating a higher profile bone plate. These retaining devices block the anchors to prevent them from backing out of the plate. Measures taken to retain the screws in the bone plate and keep the screws engaged in the bony portion can improve their function and avoid problems associated with bone screw backout.
There can be some problems associated with prior retaining devices. For example, in prior retaining devices, the head of one or more of the anchors may interfere with positioning and alignment of the retaining device relative to the anchor. Prior retaining devices may not be employed with one or more of the anchors if the anchors move relative to the plate, or if multiple anchors associated with the retaining device are not at the same position relative to the plate. Also, prior retaining devices can be difficult to handle, install and/or manipulate.
There remains a need for instruments and methods that can be employed for efficiently and effectively preventing backout of anchors relative to a bone plate and maintaining the engagement between the anchors and a bony segment.